Fuel injection device for a compressionignited internal combustion engine

ABSTRACT

FUEL INJECTION DEVICE FOR A COMPRESSION-IGNITED INTERNAL COMBUSTION ENGINE. THE DEVICE IS IN THE FORM OF A TAKEOFF DEVICE MODIFYING THE LAW AND DURATION OF THE INJECTION. AN ADJUSTABLE CLOSING ELEMENT ACTING AS CANCELLING MEANS IS LOCATED IN A PASSAGEWAY HAVING A CONSTRICTION AND CONNECTING THE TAKEOFF CHAMBER OF THE DEVICE TO THE INJECTION PUMP. THE POSITION CLOSING ELEMENT IS CONTROLLED BY A PARAMETER WHICH IS A FUNCTION OF A CONDITION OF OPERATION OF THE ENGINE.

United States Patent Inventor Jean Moulln Chatou, France Appl. No. 801,961 Filed Feb. 25, 1969 Patented June 28, 1971 Assignee Automobiles Peugeot Paris, France Priority Mar. 5, 1968 France 142354 FUEL INJECTION DEVICE FOR A COMPRESSION- IGNITED INTERNAL COMBUSTION ENGINE 9 Claims, 7 Drawing Figs.

US. Cl. 417/275, 92/605, 123/139 Int. Cl. ..F04b 49/00, I-Olb 31/14, F22b 7/00 Field of Search 103/37; 230/21; 123/139.14

. 1 i' 114 i 117 06 l 102 i 10 I 101 Primary Examiner-William L. Freeh Attorneys-Bums, Doane and Benedict and Swecker and Mathis ABSTRACT: Fuel injection device for a compression-ignited internal combustion engine. The device is in the form of a takeoff device modifying the law and duration of the injection. An adjustable closing element acting as cancelling means is located in a passageway having a constriction and connecting the takeoff chamber of the device to the injection pump. The position closing element is controlled by a parameter which is a function of a condition of operation of the engine.

SHEET 1 OF 2 ATENTED JUNZB M 8. S r Iii/Ill 1 Q2 me /0% 0 8 2 /0/// FUEL INJECTION DEVICE FOR A COMPRESSION- IGNITED INTERNAL COMBUSTION ENGINE The present invention relates to fuel injection devices for compression-ignited internal combustion engines of the type in which, for the purpose of varying the law and duration of the fuel injection, there is provided a takeoff device comprising a takeoff chamber connected to the delivery chamber of the injection pump through a passageway having a constriction, and cancelling means for neutralizing the modifying ef fect of said takeoff chamber on the injection law.

The invention provides an injection device of the type defined hereinbefore wherein said cancelling means comprise an adjustable closing element which is located in said passageway connecting said delivery chamber of the injection pump to said takeoff chamber, the position of said cancelling means being controlled by a parameter which is a function of the condition of operation of the engine.

When the closing element is in the passageway-opening position, the injection law is modified. When, on the other hand, the closing element is in the passageway-closing position, the takeoff chamber is isolated from the delivery chamber of the pump and the presence of said takeoff chamber no longer has any effect on the injection law.

The closing element can be controlled by the parameter through mechanical, hydraulic or electromagnetic means.

Further features and advantages of the invention will be apparent from the ensuing description with reference to the accompanying drawings.

In the drawings:

FIG. 1 is an assembly view of one embodiment of an injection device according to the invention, and

FIGS. 27 are partial sectional views of other embodiments of the invention.

In the embodiment shown in FIG. 1, the invention is applied to an injection device comprising a feed pump A which delivers fuel by way of pipes B to injectors C.

Disposed in the pump A is the delivery chamber 101 in which the piston 102 compresses the fuel and delivers it by way of a distributor recess 103 and outlet apertures 104.

The modifying device comprises a takeoff or fuel removing chamber 105 connected to the delivery chamber of the pump through a passageway having a constriction 106. A piston 107 constitutes a movable wall of the takeoff chamber and is combined with a return spring 108 and an abutment 109 which determines the maximum takeoff capacity of the chamber 105 by limiting the travel of the piston 107.

The cancelling means proper comprise a key closing element 110 rotatably mounted in a cavity 111 which constitutes a body located in the passageway 112 which connects the takeoff chamber 105 to the delivery chamber 101. The key 110 comprises an orifice 113 whereby it is possible to allow the fuel to pass between the two chambers 101 and 105 or stop this fuel passing depending on the angular position of the key.

In the presently described embodiment, the closing element 110 is controlled by the position of the acceleration lever 114 of the pump. For this purpose, a lever 115 integral with the key 110 is connected to the acceleration lever 114 of the pump by a link 116.

The extreme positions of the pump lever 114 are defined by an idling speed abutment 117 and a maximum speed abutment 118.

Under these conditions, the injection dice operates in the following manner:

At idling speed, and for conditions of operation of the engine corresponding to the positions of the lever 114 of the pump in the vicinity of the idling speed abutment 117, the key 110 allows the takeoff device to produce the desired modifying effect on the injection law of the pump by taking off or removing in the chamber 105 at the start of the injection a certain amount of fuel which is returned to the pump, at the end of the injection, at the start of the suction period of this pump.

For conditions of operation corresponding to the other positions of the takeoff 114 of the pump, the key 110 isolates the takeoff device which no longer produces any effect on the injection law.

In the embodiment of the invention shown in FIG. 2, the takeoff chamber does not comprise a movable wall and therefore has a fixed volume. The amount of fuel taken off upon each injection results from the compressibility of this fuel in this chamber under the effect of the injection pressure.

In the embodiment shown in FIG. 3, the constricted orifice between the takeoff chamber 105 and the delivery chamber 101 is located at 106 in the closing element 110.

The closing element can be arranged to pass progressively between the fully open position and the closing position so as to reduce and render progressive the effect of the device over a whole range of operation ofthe engine.

In the embodiment shown in FIG. 4, this element consists of a slide valve 110.

The communication between the fixed takeoff chamber and the delivery chamber of the pump can be made permanent or temporary through recesses or apertures formed in the element of the pump which distributes the fuel to the injectors. Thus, in the embodiment shown in FIG. 5, apertures and 121 formed in the fuel distributing piston 102 of the pump put the two chambers 101 and 105 in communication when the injection is effected by way of the recess 103 and passageway 104.

Note that the closing element can be combined with one of the existing parts of the pump, such as the regulating slide valve. Thus there has been shown partly in FIG. 6 a pump of known type comprising a regulating slide valve 122 whose normal function is to meter, in accordance with the conditions of operation of the engine, the amount of fuel delivered by the pump upon each injection. This function is performed by means of a ramp 123 which, depending on the position of the slide valve, retards to a varying extent the feeding of the fuel to the cylinder 101 by way of the passageways 124, 125, 126 and 119 (during the feeding stage, the piston 102 is in its innermost position and the passageways 125 and 126 intercommunicate). According to the invention, the slide valve 122 also performs the function of the cancelling means of the device owing to the provision of an extension portion 110 provided with a second ramp 127 which closes to a varying ex tent, depending on the position of the slide valve, the passageway interconnecting the takeoff chamber 105 and the delivery chamber 101 ofthe pump.

This slide valve 122 can be controlled mechanically, hydraulically or electromagnetically and the same is true of each of the other closing elements shown, the control of the closing element being if desired controlled by any parameter other than the acceleration.

For example, it is known that there exists in pumps of known type a fuel feed circuit termed the transfer" circuit whose pressure varies in accordance with a law determined as a function of the conditions of operation of the engine. The position of the closing element can be controlled directly by this pressure.

A device comprising such a control is shown in FIG. 7 by way of example. The closing element is a slide valve 110 comprising in its middle portion a recess 128. This slide valve is subjected on its end 129 to the transfer pressure through a passageway 130 and on its end 131 to the opposing action of a spring 132. This spring bears against a plug 133 having a pipe 134 by way of which leakage of fuel returns to the fuel tank.

Under conditions of operation in which the effect of the transfer pressure balances the return force of the spring 132, the slide valve 110 occupies such position that the recess '1 28 allows the passage of the fuel into the passageway 111 interconnecting the delivery chamber 101 of the pump and the takeoff chamber 105 of the device. Under the conditions of operation of the engine in which the transfer is weaker or stronger, the slide valve 110" occupies a position of equilibrium which is different and the connecting passageway 11 is closed by the cylindrical portions 135 or 136 of the slide valve.

Although specific embodiments of the invention have been described, many modifications and changes may be made therein without departing from the scope of the invention as defined in the appended claims.

Iclaim:

1. In a fuel injection device for a compression-ignited internal combustion engine having a fuel injection pump including a delivery chamber communicating with an injector of the engine, said device comprising a takeoff chamber for deducting a part of the fuel delivered by said delivery chamber, said delivery chamber of the injection pump being connection to said takeoff chamber by way of a passageway having a constriction and cancelling means, the feature that said cancelling means comprise an adjustable closing element located in said passageway and movable between a closing position in which it closes said passageway and an opening position in which said passageway is open, said closing element being adapted to be connected to means responsive to a parameter which is a function of the condition of operation of the engine, so that said means responsive to a parameter move said element to a position which varies in accordance with said condition of operation, whereby the amount of fuel delivered by said delivery chamber to said injector is modified in accordance with said condition of operation.

2. A fuel injection device as claimed in claim 1, wherein said closing element consists of a key rotatable in a fixed body defining a part of said passageway.

3. A fuel injection device as claimed in claim 1, wherein said constriction between said delivery chamber of the pump and said takeofi' camber is located in said closing element.

4. A fuel injection device as claimed in claim 1, wherein said closing element is a slidable slide valve.

5. A fuel injection device as claimedin claim 4, wherein said slide valve comprises a recess having a sloping profile which affords a progressive closure of said passageway.

6. A fuel injection device as claimed in claim 1, wherein said closing element is connected to an acceleration lever of said engine.

7. A fuel injection device as claimed in claim 1, wherein said closing element is combined with a regulation slide valve of the injection pump of said engine.

8. A fuel injection device as claimed in claim 1, wherein said closing element is combined with a moving part of the injection pump of said engine.

9. A fuel injection device as claimed in claim 1, said device being connected to be fed by a pump having a transfer pressure, said closing element being subjected to the action of said transfer pressure of the pump. 

